Antibiotic resistance assessment of lactic acid bacteria isolated from traditional Andean fermented sausages

Abstract

Antimicrobial susceptibility profiles of lactic acid bacteria (LAB) from different foods, including fermented dry sausages have been described. Several studies suggest that the presence of antimicrobial resistances in the microbial communities of fermented foods is a consequence of the use of antibiotics in animal farming. In this study we have analyzed the antimicrobial resistance profiles of LAB from Andean traditional fermented sausages, produced in areas characterized by a low anthropic impact. These artisanal fermented sausages produced in the northern province of Jujuy, Argentina are usually prepared with 75% of llama meat, 19% of pork fat, together with salt, sodium nitrite, sucrose and species (white pepper, clove and garlic). A total of 48 Lactobacillus sakei strains isolated from llama fermented sausages presenting different RAPD profiles were selected for the antimicrobial susceptibility tests. All the antibiotics recommended for the EFSA (2012) were included in the assay: ampicillin and vancomycin as inhibitors of cell wall synthesis, clindamycin, chloramphenicol, erythromycin, gentamicin, kanamycin, streptomycin and tetracycline as inhibitors of protein synthesis. The minimum inhibitory concentration of antibiotics (MICs, µg/mL) for all bacteria was determined by the broth microdilution method (International Standard [ISO 10932:2010(E)]. Differences in the antimicrobial susceptibility were observed among the strains. All of them were sensitive to erythromycin, tetracycline and clindamycine. Resistant to ampicillin was observed only in a multiresistant strain presenting a resistant profile to four antibiotics. Most of the strains were resistant to the aminoglycosides, mainly to streptomycin (22 strains) but also to kanamycin (5 strains) and gentamycin (5 strains). The rest of the strains were sensitive to all the antibiotics tested. This data indicates that also in marginal areas the resistance to clinically relevant antibiotics is widespread in the adventitious bacterial communities responsible for meat fermentation, although the high prevalence of aminoglycoside resistance may be related to intrinsic resistance mechanisms.